膜下滴灌调亏对马铃薯块茎形成期光合生理及产量的影响

Effect of Water Deficit under Mulched Drip Irrigation on Photosynthetic Physiological Indexes and Yield of Potato During Tuber Formation

研究了绿洲区膜下滴灌调亏对马铃薯块茎形成期叶片光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)及产量和水分利用效率(WUE)的影响。结果表明,马铃薯Pn日变化呈先降低、后升高、再降低的"双峰"曲线;轻度调亏和充分供水处理Tr日变化呈"单峰"曲线,中度调亏处理Tr日变化趋势不明显。07:00—11:00马铃薯Gs以轻度调亏处理最大,充分供水处理最小;13:00—19:00Gs马铃薯以CK处理最大,中度调亏处理最小。充分供水或轻度水分亏缺时光合有效辐射、气温和叶温是影响Tr的主导因素,而中度亏缺时光合有效辐射的影响小于气温和叶温。马铃薯叶片水分利用效率(WUEf)与Pn显著正相关,与Tr显著负相关,Tr对WUEf的直接影响大于Pn。轻度调亏、中度调亏处理马铃薯产量比充分供水处理显著降低12.7%、22.9%,WUE显著提高14.2%、10.6%。

Effects of water deficit under mulched drip irrigation on leaf photosynthetic rate （Pn）, transpira- tion rate （Tr）, stomatal conductance （Gs）, yield and water use efficiency （WUE） of potato during tuber formation were explored in Hexi oasis region. The results showed that potato Pn varied as double-peak curves, and both Tr in low water deficit potato （WDL） and full water application （CK） varied as single- peak curves, but the trend in medium water deficit （WDM） was not obvious. The highest and the lowest Gs of potato appeared in the treatments of WDL and CK respectively from 07 ..00 to 11：00, while those ap- peared in CK and WDM from 13.00 to 19..00. Photosynthetic available radiation （PAR）, air temperature （Ta）, and leaf temperature （TI） were three dominant elements affecting Tr under full water application and low water deficit, but effect of PAR was lower than Ta and Tl under medium water deficit. Signifi- cant positive and negative correlations were respectively found between water use efficiency of potato leaf （WUEf） and Pn, and between WUEf and Tr. Direct effect of Tr on WUEf was more important than Pn. Potato yield significantly （p〈0.05） decreased by 12.7% and 22.9% while WUE increased significantly by 14.2% and 10.6% respectively in the treatments of WDL and WDM compared to CK.